1. Technical Field
The present invention relates to a physical quantity sensor, an electronic apparatus, and a moving object.
2. Related Art
An angular rate sensor which includes a detection circuit is known in the related art, for example, as described in JP-A-2014-149229. The detection circuit includes a differential amplifier circuit (referred to as a differential amplifier in JP-A-2014-149229), and a synchronous detection circuit (referred to as a synchronization detector in JP-A-2014-149229) which performs synchronous detection of a signal that is output from a differential amplifier.
In the detection circuit described in JP-A-2014-149229, an amplification rate of a differential amplifier circuit is set variably, and if an excessive impact is applied, the amplification rate decreases. Accordingly, an output of the differential amplifier circuit is prevented from being saturated. In addition, a synchronous detection circuit also includes an operational amplifier, and when the amplification rate of the differential amplifier circuit decreases, an amplification rate of the synchronous detection circuit increases. Accordingly, a multiplication value of the amplification rate of the differential amplifier circuit and the amplification rate of the synchronous detection circuit becomes constant.
However, in an angular rate sensor described in JP-A-2014-149229, if the amplification rate of the differential amplifier decreases, the amplification rate of the synchronization detector increases, and thus, if an excessive impact is applied, the amplification rate of the synchronization detector can be greater than that of the differential amplifier. In general, saturation voltages of the circuits are the same as each other, and thus, there is a possibility that an output of an operational amplifier included in the synchronization detector or an output of an amplifier provided in a subsequent stage thereof is saturated.
As a result, there is a problem that a correct signal is not output from an amplifier provided in a subsequent stage, and thus, a sensor can output incorrect angular rate.